In order to dissipate a large quantity of heat that is generated in a semiconductor device or electronic devices, a method has been developed to obtain a high cooling performance by bringing a heat absorber into contact with such heat generating devices, and flowing a refrigerant inside of the heat absorber. By boiling the refrigerant with the heat absorber, it is possible to obtain a higher cooling effect. As a method of circulating the refrigerant between the heat absorbing portion and the heat dissipating portion, traditionally a method that employs a pump was generally used. In the case of a boiling heat transfer device, a thermal siphon-type cooling structure has been proposed that, by installing a heat absorbing portion in the lower part of the cooler and a heat dissipating portion above the cooler, does not required a pump by employing the principle of vapor collecting upward with respect to the direction of gavity due to the difference in density between the vapor that is generated and the liquid (for example, refer to Patent Documents 1 to 5).
The boiling heat transfer device that is disclosed in Patent Document 1 has a thin-type refrigerant bath whose planar shape is almost trapezoidal, with a boiling space provided within. The portion that comes into contact with a heat generator (computer chip) is provided on the bottom surface of the refrigerant bath, and a vapor side header tank and a liquid side header tank that extend from the refrigerant tank in a perpendicular direction and are continuous with the interior space of the refrigerant tank are provided on the upper surface of the refrigerant tank. Both header tanks are connected by a plurality of heat dissipating tubes. Heat dissipating fins are installed between the heat dissipating tubes. In this boiling heat transfer device, the portion of the refrigerant tank that is in contact with the heat generator is provided along the upper base of the trapezoid shape, and the connection portion between the gas side/liquid side header tanks of the refrigerant tank is provided near the end portions on the lower base of the trapezoid shape.
Patent Document 2 discloses a CPU cooling device that leads refrigerant vapor from a vaporizer that is in contact with a CPU, which is a heat generator, to a condenser via a vapor flow passage, and returns the refrigerant that has been liquefied in the condenser to the vaporizer via a liquid flow passage. In the cooling device, a zigzagging pipe that is provided in a manner connected to the heat dissipating fins is installed in the condenser. The vapor from the vapor flow passage flows in from the inflow portion of the pipe, and refrigerant liquid from the outflow portion of the pipe to the liquid flow passage flows out.
Patent Document 3 discloses a thermo-siphon type heat transfer body. The space between a heat absorbing side header block and a heat radiating side header block, in which X-direction coolant channels and Y-direction coolant channels are respectively formed, is connected by a plurality of coolant tubes. Corrugated fins are provided between the coolant tubes. In this thermo-siphon type heat transfer body, the heat absorbing side header block is disposed on the lower side, and the heat radiating side header block is disposed on the upper side, and a semiconductor element is closely attached to the undersurface of the heat absorbing side header block.
Patent Document 4 discloses a liquid cooling system. A radiator is provided in a storage container in which a heat exchange circulating solution and vapor thereof are stored. Moreover, a solution delivery port and a gas-liquid two-phase fluid feeding port of the storage container are coupled by a pipe of which a portion passes through the storage container. The pipe has a solution delivery pipe portion that is coupled to the solution delivery port and enters the storage container, an in-container pipe portion that is in the storage container, and a gas-liquid two-phase fluid feeding pipe portion that comes out from the storage container and is coupled to the gas-liquid two-phase fluid feeding port. A heating heat exchanger that acts as a radiator for a heat-generating body such as an electronic device is provided in the gas-liquid two-phase fluid feeding pipe portion.
Patent Document 5 discloses a cooling device that is an integrated thermosiphon in which a heat receiving portion and a heat dissipating portion are mounted in the same housing. A plurality of condenser tubes are arranged above the boiler plate, with a plurality of pyramid-shaped fins formed on the surface. Vapor chambers are constituted between the condenser tubes and the boiler plate. In this cooling device, the condenser tubes are sandwiched by revolving fins for heat dissipation. The vapor that is produced in the vapor chambers rises up through the condenser tubes, and is liquefied on the walls thereof.